-- Migration: Update reports for pay period support and snapshot labor amounts
-- Reports now cover a date range and store calculated labor_share at time of addition

-- 1. Add status enum for report workflow
CREATE TYPE report_status AS ENUM ('DRAFT', 'FINALIZED', 'PAID');

-- 2. Alter reports table: date → start_date/end_date, add status
ALTER TABLE reports
    ADD COLUMN start_date DATE,
    ADD COLUMN end_date DATE,
    ADD COLUMN status report_status NOT NULL DEFAULT 'DRAFT';

-- Migrate existing data (use date as both start and end)
UPDATE reports SET start_date = date, end_date = date WHERE start_date IS NULL;

-- Make date columns required
ALTER TABLE reports
    ALTER COLUMN start_date SET NOT NULL,
    ALTER COLUMN end_date SET NOT NULL;

-- Drop old column and constraint
ALTER TABLE reports DROP CONSTRAINT IF EXISTS reports_team_profile_id_date_key;
ALTER TABLE reports DROP COLUMN date;

-- Add check: end_date >= start_date
ALTER TABLE reports ADD CONSTRAINT reports_date_range_check
    CHECK (end_date >= start_date);

-- Index for querying by period
CREATE INDEX idx_reports_period ON reports(start_date, end_date);
CREATE INDEX idx_reports_status ON reports(status);

-- 3. Add labor_share snapshot to report_services
-- This stores the calculated amount at time of addition (immutable for payroll)
ALTER TABLE report_services
    ADD COLUMN labor_share NUMERIC(10,2) NOT NULL DEFAULT 0.00;

-- Remove default after backfill
ALTER TABLE report_services ALTER COLUMN labor_share DROP DEFAULT;

-- 4. Add labor_share snapshot to report_projects
ALTER TABLE report_projects
    ADD COLUMN labor_share NUMERIC(10,2) NOT NULL DEFAULT 0.00;

ALTER TABLE report_projects ALTER COLUMN labor_share DROP DEFAULT;

-- 5. Prevent same service in multiple reports for same team member
-- A completed service should only be paid once per team member
-- Using trigger-based approach since PostgreSQL doesn't support subqueries in index expressions

-- Create a function to check uniqueness
CREATE OR REPLACE FUNCTION check_report_service_unique()
RETURNS TRIGGER AS $$
BEGIN
    IF EXISTS (
        SELECT 1 FROM report_services rs
        JOIN reports r ON rs.report_id = r.id
        WHERE rs.service_id = NEW.service_id
        AND r.team_profile_id = (SELECT team_profile_id FROM reports WHERE id = NEW.report_id)
        AND rs.id IS DISTINCT FROM NEW.id
    ) THEN
        RAISE EXCEPTION 'Service % is already in another report for this team member', NEW.service_id;
    END IF;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trg_report_service_unique
    BEFORE INSERT OR UPDATE ON report_services
    FOR EACH ROW EXECUTE FUNCTION check_report_service_unique();

-- Same for projects
CREATE OR REPLACE FUNCTION check_report_project_unique()
RETURNS TRIGGER AS $$
BEGIN
    IF EXISTS (
        SELECT 1 FROM report_projects rp
        JOIN reports r ON rp.report_id = r.id
        WHERE rp.project_id = NEW.project_id
        AND r.team_profile_id = (SELECT team_profile_id FROM reports WHERE id = NEW.report_id)
        AND rp.id IS DISTINCT FROM NEW.id
    ) THEN
        RAISE EXCEPTION 'Project % is already in another report for this team member', NEW.project_id;
    END IF;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trg_report_project_unique
    BEFORE INSERT OR UPDATE ON report_projects
    FOR EACH ROW EXECUTE FUNCTION check_report_project_unique();