--
-- Sources queries
-- All SQL for api/routes/sources.js
--

SET search_path TO dataflow, public;

-- ── CRUD ─────────────────────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION list_sources()
RETURNS SETOF dataflow.sources AS $$
    SELECT * FROM dataflow.sources ORDER BY name;
$$ LANGUAGE sql STABLE;

CREATE OR REPLACE FUNCTION get_source(p_name TEXT)
RETURNS dataflow.sources AS $$
    SELECT * FROM dataflow.sources WHERE name = p_name;
$$ LANGUAGE sql STABLE;

CREATE OR REPLACE FUNCTION create_source(p_name TEXT, p_dedup_fields TEXT[], p_config JSONB DEFAULT '{}')
RETURNS dataflow.sources AS $$
    INSERT INTO dataflow.sources (name, dedup_fields, config)
    VALUES (p_name, p_dedup_fields, p_config)
    RETURNING *;
$$ LANGUAGE sql;

CREATE OR REPLACE FUNCTION update_source(p_name TEXT, p_dedup_fields TEXT[] DEFAULT NULL, p_config JSONB DEFAULT NULL)
RETURNS dataflow.sources AS $$
    UPDATE dataflow.sources
    SET dedup_fields = COALESCE(p_dedup_fields, dedup_fields),
        config       = COALESCE(p_config, config),
        updated_at   = CURRENT_TIMESTAMP
    WHERE name = p_name
    RETURNING *;
$$ LANGUAGE sql;

CREATE OR REPLACE FUNCTION delete_source(p_name TEXT)
RETURNS TEXT AS $$
    DELETE FROM dataflow.sources WHERE name = p_name RETURNING name;
$$ LANGUAGE sql;

-- ── Import log ────────────────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION get_import_log(p_source_name TEXT)
RETURNS SETOF dataflow.import_log AS $$
    SELECT * FROM dataflow.import_log
    WHERE source_name = p_source_name
    ORDER BY imported_at DESC;
$$ LANGUAGE sql STABLE;

-- ── Stats ─────────────────────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION get_source_stats(p_source_name TEXT)
RETURNS TABLE (total_records BIGINT, transformed_records BIGINT, pending_records BIGINT) AS $$
    SELECT
        COUNT(*)                                         AS total_records,
        COUNT(*) FILTER (WHERE transformed IS NOT NULL)  AS transformed_records,
        COUNT(*) FILTER (WHERE transformed IS NULL)      AS pending_records
    FROM dataflow.records
    WHERE source_name = p_source_name;
$$ LANGUAGE sql STABLE;

-- ── Fields ────────────────────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION get_source_fields(p_source_name TEXT)
RETURNS TABLE (key TEXT, origins TEXT[]) AS $$
    SELECT key, array_agg(DISTINCT origin ORDER BY origin) AS origins
    FROM (
        SELECT f->>'name'  AS key, 'schema'              AS origin
        FROM dataflow.sources, jsonb_array_elements(config->'fields') f
        WHERE name = p_source_name AND config ? 'fields'
        UNION ALL
        SELECT jsonb_object_keys(data) AS key, 'raw'     AS origin
        FROM dataflow.records WHERE source_name = p_source_name
        UNION ALL
        SELECT output_field AS key, 'rule: ' || name     AS origin
        FROM dataflow.rules WHERE source_name = p_source_name
        UNION ALL
        SELECT jsonb_object_keys(output) AS key, 'mapping' AS origin
        FROM dataflow.mappings WHERE source_name = p_source_name
    ) keys
    GROUP BY key
    ORDER BY key;
$$ LANGUAGE sql STABLE;

-- ── View data (dynamic sort via EXECUTE) ──────────────────────────────────────

CREATE OR REPLACE FUNCTION get_view_data(
    p_source_name TEXT,
    p_limit       INT  DEFAULT 100,
    p_offset      INT  DEFAULT 0,
    p_sort_col    TEXT DEFAULT NULL,
    p_sort_dir    TEXT DEFAULT 'asc'
)
RETURNS JSON AS $$
DECLARE
    v_exists BOOLEAN;
    v_order  TEXT := '';
    v_rows   JSON;
BEGIN
    SELECT EXISTS (
        SELECT 1 FROM information_schema.views
        WHERE table_schema = 'dfv' AND table_name = p_source_name
    ) INTO v_exists;

    IF NOT v_exists THEN
        RETURN json_build_object('exists', FALSE, 'rows', '[]'::json);
    END IF;

    IF p_sort_col IS NOT NULL AND EXISTS (
        SELECT 1 FROM information_schema.columns
        WHERE table_schema = 'dfv'
          AND table_name   = p_source_name
          AND column_name  = p_sort_col
    ) THEN
        v_order := ' ORDER BY ' || quote_ident(p_sort_col)
                || CASE WHEN lower(p_sort_dir) = 'desc' THEN ' DESC' ELSE ' ASC' END
                || ' NULLS LAST';
    END IF;

    -- Subquery applies ORDER BY + LIMIT first, then json_agg collects in that order.
    -- json_agg on the outer query preserves column order (json not jsonb).
    EXECUTE format(
        'SELECT COALESCE(json_agg(row_to_json(t)), ''[]''::json) FROM (SELECT * FROM dfv.%I%s LIMIT %s OFFSET %s) t',
        p_source_name, v_order, p_limit, p_offset
    ) INTO v_rows;

    RETURN json_build_object('exists', TRUE, 'rows', v_rows);
END;
$$ LANGUAGE plpgsql STABLE;

-- ── Import (deduplication) ────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION import_records(p_source_name TEXT, p_data JSONB)
RETURNS JSON AS $$
DECLARE
    v_dedup_fields TEXT[];
    v_record       JSONB;
    v_dedup_key    TEXT;
    v_inserted     INTEGER := 0;
    v_duplicates   INTEGER := 0;
    v_log_id       INTEGER;
BEGIN
    SELECT dedup_fields INTO v_dedup_fields
    FROM dataflow.sources WHERE name = p_source_name;

    IF v_dedup_fields IS NULL THEN
        RETURN json_build_object('success', false, 'error', 'Source not found: ' || p_source_name);
    END IF;

    FOR v_record IN SELECT * FROM jsonb_array_elements(p_data) LOOP
        v_dedup_key := dataflow.generate_dedup_key(v_record, v_dedup_fields);
        BEGIN
            INSERT INTO dataflow.records (source_name, data, dedup_key)
            VALUES (p_source_name, v_record, v_dedup_key);
            v_inserted := v_inserted + 1;
        EXCEPTION WHEN unique_violation THEN
            v_duplicates := v_duplicates + 1;
        END;
    END LOOP;

    INSERT INTO dataflow.import_log (source_name, records_imported, records_duplicate)
    VALUES (p_source_name, v_inserted, v_duplicates)
    RETURNING id INTO v_log_id;

    RETURN json_build_object('success', true, 'imported', v_inserted, 'duplicates', v_duplicates, 'log_id', v_log_id);
END;
$$ LANGUAGE plpgsql;

-- ── Transformations ───────────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION dataflow.jsonb_merge(a JSONB, b JSONB)
RETURNS JSONB AS $$
    SELECT COALESCE(a, '{}') || COALESCE(b, '{}')
$$ LANGUAGE sql IMMUTABLE;

DROP AGGREGATE IF EXISTS dataflow.jsonb_concat_obj(JSONB);
CREATE AGGREGATE dataflow.jsonb_concat_obj(JSONB) (
    sfunc    = dataflow.jsonb_merge,
    stype    = JSONB,
    initcond = '{}'
);

DROP FUNCTION IF EXISTS apply_transformations(TEXT, INTEGER[]);
CREATE OR REPLACE FUNCTION apply_transformations(
    p_source_name TEXT,
    p_record_ids  INTEGER[] DEFAULT NULL,
    p_overwrite   BOOLEAN   DEFAULT FALSE
) RETURNS JSON AS $$
WITH
qualifying AS (
    SELECT id, data FROM dataflow.records
    WHERE source_name = p_source_name
      AND (p_overwrite OR transformed IS NULL)
      AND (p_record_ids IS NULL OR id = ANY(p_record_ids))
),
rx AS (
    SELECT
        q.id,
        r.name     AS rule_name,
        r.sequence,
        r.output_field,
        r.retain,
        r.function_type,
        COALESCE(mt.rn, rp.rn, 1) AS result_number,
        CASE WHEN array_length(mt.mt, 1) = 1 THEN to_jsonb(mt.mt[1]) ELSE to_jsonb(mt.mt) END AS match_val,
        to_jsonb(rp.rp) AS replace_val
    FROM dataflow.rules r
    INNER JOIN qualifying q ON q.data ? r.field
    LEFT JOIN LATERAL regexp_matches(q.data ->> r.field, r.pattern, r.flags)
        WITH ORDINALITY AS mt(mt, rn) ON r.function_type = 'extract'
    LEFT JOIN LATERAL regexp_replace(q.data ->> r.field, r.pattern, r.replace_value, r.flags)
        WITH ORDINALITY AS rp(rp, rn) ON r.function_type = 'replace'
    WHERE r.source_name = p_source_name AND r.enabled = true
),
agg_matches AS (
    SELECT
        id, rule_name, sequence, output_field, retain, function_type,
        CASE function_type
            WHEN 'replace' THEN jsonb_agg(replace_val) -> 0
            ELSE
                CASE WHEN max(result_number) = 1
                    THEN jsonb_agg(match_val ORDER BY result_number) -> 0
                    ELSE jsonb_agg(match_val ORDER BY result_number)
                END
        END AS extracted
    FROM rx
    GROUP BY id, rule_name, sequence, output_field, retain, function_type
),
linked AS (
    SELECT
        a.id, a.sequence, a.output_field, a.retain, a.extracted, m.output AS mapped
    FROM agg_matches a
    LEFT JOIN dataflow.mappings m ON
        m.source_name = p_source_name
        AND m.rule_name = a.rule_name
        AND m.input_value = a.extracted
    WHERE a.extracted IS NOT NULL
),
rule_output AS (
    SELECT
        id, sequence,
        CASE
            WHEN mapped IS NOT NULL THEN
                mapped || CASE WHEN retain THEN jsonb_build_object(output_field, extracted) ELSE '{}'::jsonb END
            ELSE jsonb_build_object(output_field, extracted)
        END AS output
    FROM linked
),
record_additions AS (
    SELECT id, dataflow.jsonb_concat_obj(output ORDER BY sequence) AS additions
    FROM rule_output GROUP BY id
),
updated AS (
    UPDATE dataflow.records rec
    SET transformed    = rec.data || COALESCE(ra.additions, '{}'::jsonb),
        transformed_at = CURRENT_TIMESTAMP
    FROM qualifying q
    LEFT JOIN record_additions ra ON ra.id = q.id
    WHERE rec.id = q.id
    RETURNING rec.id
)
SELECT json_build_object('success', true, 'transformed', count(*)) FROM updated
$$ LANGUAGE sql;

CREATE OR REPLACE FUNCTION reprocess_records(p_source_name TEXT)
RETURNS JSON AS $$
    SELECT dataflow.apply_transformations(p_source_name, NULL, TRUE)
$$ LANGUAGE sql;

-- ── View generation ───────────────────────────────────────────────────────────

CREATE OR REPLACE FUNCTION generate_source_view(p_source_name TEXT)
RETURNS JSON AS $$
DECLARE
    v_config JSONB;
    v_field  JSONB;
    v_cols   TEXT := '';
    v_sql    TEXT;
    v_view   TEXT;
BEGIN
    SELECT config INTO v_config FROM dataflow.sources WHERE name = p_source_name;

    IF v_config IS NULL OR NOT (v_config ? 'fields') OR jsonb_array_length(v_config->'fields') = 0 THEN
        RETURN json_build_object('success', false, 'error', 'No schema fields defined for this source');
    END IF;

    FOR v_field IN SELECT * FROM jsonb_array_elements(v_config->'fields') LOOP
        IF v_cols != '' THEN v_cols := v_cols || ', '; END IF;

        IF v_field->>'expression' IS NOT NULL THEN
            DECLARE
                v_expr TEXT := v_field->>'expression';
                v_ref  TEXT;
            BEGIN
                WHILE v_expr ~ '\{[^}]+\}' LOOP
                    v_ref  := substring(v_expr FROM '\{([^}]+)\}');
                    v_expr := replace(v_expr, '{' || v_ref || '}', format('(transformed->>%L)::numeric', v_ref));
                END LOOP;
                v_cols := v_cols || format('%s AS %I', v_expr, v_field->>'name');
            END;
        ELSE
            CASE v_field->>'type'
                WHEN 'date'    THEN v_cols := v_cols || format('(transformed->>%L)::date    AS %I', v_field->>'name', v_field->>'name');
                WHEN 'numeric' THEN v_cols := v_cols || format('(transformed->>%L)::numeric AS %I', v_field->>'name', v_field->>'name');
                ELSE                v_cols := v_cols || format('transformed->>%L             AS %I', v_field->>'name', v_field->>'name');
            END CASE;
        END IF;
    END LOOP;

    CREATE SCHEMA IF NOT EXISTS dfv;
    v_view := 'dfv.' || quote_ident(p_source_name);
    EXECUTE format('DROP VIEW IF EXISTS %s', v_view);
    v_sql := format(
        'CREATE VIEW %s AS SELECT %s FROM dataflow.records WHERE source_name = %L AND transformed IS NOT NULL',
        v_view, v_cols, p_source_name
    );
    EXECUTE v_sql;

    RETURN json_build_object('success', true, 'view', v_view, 'sql', v_sql);
END;
$$ LANGUAGE plpgsql;