--
-- 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_constraint_fields TEXT[], p_config JSONB DEFAULT '{}', p_global_picklist BOOLEAN DEFAULT true)
RETURNS dataflow.sources AS $$
    INSERT INTO dataflow.sources (name, constraint_fields, config, global_picklist)
    VALUES (p_name, p_constraint_fields, p_config, p_global_picklist)
    RETURNING *;
$$ LANGUAGE sql;

CREATE OR REPLACE FUNCTION update_source(p_name TEXT, p_constraint_fields TEXT[] DEFAULT NULL, p_config JSONB DEFAULT NULL, p_global_picklist BOOLEAN DEFAULT NULL)
RETURNS dataflow.sources AS $$
    UPDATE dataflow.sources
    SET constraint_fields = COALESCE(p_constraint_fields, constraint_fields),
        config            = COALESCE(p_config, config),
        global_picklist   = COALESCE(p_global_picklist, global_picklist),
        updated_at        = CURRENT_TIMESTAMP
    WHERE name = p_name
    RETURNING *;
$$ 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 ────────────────────────────────────────────────────────────────

-- ── 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',
    p_filters     JSONB   DEFAULT NULL   -- [{col, pattern}, ...] — postgres regex (~*)
)
RETURNS JSON AS $$
DECLARE
    v_exists  BOOLEAN;
    v_where   TEXT := '';
    v_order   TEXT := '';
    v_rows    JSON;
    v_filter  JSONB;
    v_col     TEXT;
    v_pattern TEXT;
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;

    -- Build WHERE from filters (validate each column exists in the view)
    IF p_filters IS NOT NULL THEN
        FOR v_filter IN SELECT value FROM jsonb_array_elements(p_filters) LOOP
            v_col     := v_filter->>'col';
            v_pattern := v_filter->>'pattern';
            IF v_pattern IS NOT NULL AND v_pattern <> '' AND EXISTS (
                SELECT 1 FROM information_schema.columns
                WHERE table_schema = 'dfv'
                  AND table_name   = p_source_name
                  AND column_name  = v_col
            ) THEN
                v_where := v_where ||
                    CASE WHEN v_where = '' THEN ' WHERE ' ELSE ' AND ' END ||
                    quote_ident(v_col) || '::text ~* ' || quote_literal(v_pattern);
            END IF;
        END LOOP;
    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;

    EXECUTE format(
        'SELECT COALESCE(json_agg(row_to_json(t)), ''[]''::json) FROM (SELECT * FROM dfv.%I%s%s LIMIT %s OFFSET %s) t',
        p_source_name, v_where, v_order, p_limit, p_offset
    ) INTO v_rows;

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

-- ── 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;

-- List saved pivot layouts for a source
CREATE OR REPLACE FUNCTION list_pivot_layouts(p_source_name TEXT)
RETURNS TABLE(id INT, source_name TEXT, layout_name TEXT, config JSONB, created_at TIMESTAMPTZ) AS $$
    SELECT id, source_name, layout_name, config, created_at
    FROM dataflow.pivot_layouts
    WHERE source_name = p_source_name
    ORDER BY layout_name;
$$ LANGUAGE sql;

-- Save (upsert) a named pivot layout
CREATE OR REPLACE FUNCTION save_pivot_layout(p_source_name TEXT, p_layout_name TEXT, p_config JSONB)
RETURNS TABLE(id INT, source_name TEXT, layout_name TEXT, config JSONB, created_at TIMESTAMPTZ) AS $$
    INSERT INTO dataflow.pivot_layouts (source_name, layout_name, config)
    VALUES (p_source_name, p_layout_name, p_config)
    ON CONFLICT (source_name, layout_name) DO UPDATE
        SET config = EXCLUDED.config
    RETURNING id, source_name, layout_name, config, created_at;
$$ LANGUAGE sql;

-- Delete a named pivot layout
CREATE OR REPLACE FUNCTION delete_pivot_layout(p_id INT)
RETURNS TABLE(id INT) AS $$
    DELETE FROM dataflow.pivot_layouts WHERE id = p_id RETURNING id;
$$ LANGUAGE sql;