#!/usr/bin/env python3
"""Emit go-api/internal/domain/resources_gen.go from the live PostgreSQL schema.

Column names, types, enum values and nullability are read out of
information_schema so they can never drift from the migrations. The per-resource
metadata below (path, default sort, default limit, operations, required fields)
comes from docs/api-contract.md and is the only hand-maintained part.

Usage: make gen-resources
"""
import collections
import json
import os
import subprocess
import sys

DB = os.environ.get("DATABASE_NAME", "Krow-force")
HOST = os.environ.get("DATABASE_HOST", "127.0.0.1")
PORT = os.environ.get("DATABASE_PORT", "5432")
USER = os.environ.get("DATABASE_USER", "postgres")


def q(sql):
    out = subprocess.run(
        ["psql", "-h", HOST, "-p", PORT, "-U", USER, "-d", DB, "-tAF", "\x1f", "-c", sql],
        capture_output=True, text=True)
    if out.returncode:
        sys.exit(out.stderr)
    return [l.split("\x1f") for l in out.stdout.strip().split("\n") if l.strip()]


# ops='' means the resource has a table and is seeded, but serves no HTTP
# endpoint (see api-contract.md §2). It still needs a descriptor so the seeder
# can write it.
META = {
 'job_postings':    dict(name='JobPosting',    path='job-postings',    sort='-created_date', limit=100, ops='List|Get|Create|Update',    req=['title']),
 'job_applications':dict(name='JobApplication',path='job-applications',sort='-ai_score',     limit=200, ops='List|Create|Update|Delete', req=['job_posting_id','applicant_name','email']),
 'ai_interviews':   dict(name='AIInterview',   path='ai-interviews',   sort='-created_date', limit=100, ops='List|Create',               req=['application_id','job_posting_id']),
 'staff':           dict(name='Staff',         path='staff',           sort='-created_date', limit=100, ops='List|Create|Update',        req=['name','email','hire_date']),
 'worker_profiles': dict(name='WorkerProfile', path='worker-profiles', sort='-krow_score',   limit=500, ops='List|Create|Update',        req=['full_name','email']),
 'courses':         dict(name='Course',        path='courses',         sort='-created_date', limit=200, ops='List|Get|Create|Update',    req=['title'], orgnull=True),
 'learning_paths':  dict(name='LearningPath',  path='learning-paths',  sort='-created_date', limit=100, ops='List',                      req=['name'],  orgnull=True),
 'role_categories': dict(name='RoleCategory',  path='role-categories', sort='-created_date', limit=100, ops='List|Create',               req=['name']),
 'certifications':  dict(name='Certification', path='certifications',  sort='-created_date', limit=200, ops='List|Create|Delete',        req=['name']),
 'user_activity':   dict(name='UserActivity',  path='user-activity',   sort='-created_date', limit=500, ops='List|Create',               req=['event_type']),
 'evidence':        dict(name='Evidence',      path='evidence',        sort='-created_date', limit=200, ops='List|Create|Update',        req=['type','worker_email']),
 'assignments':     dict(name='Assignment',    path='assignments',     sort='-created_date', limit=500, ops='List|Create',               req=['job_posting_id','worker_email','starts_at']),
 'shift_records':   dict(name='ShiftRecord',   path='shift-records',   sort='-created_date', limit=500, ops='List',                      req=[]),
 'badges':          dict(name='Badge',         path='badges',          sort='-created_date', limit=200, ops='',                          req=['name']),
}
ORDER = list(META)

# Columns the API never accepts from a request body, on every table that has
# them. The row's identity, its tenant and its timestamps are the server's.
READONLY = {'id', 'org_id', 'created_date', 'updated_date', 'legacy_id'}

# Columns that are server-owned on ONE table only.
#
# These name a *person*, and before Phase 3D a client could set them freely —
# which meant any authorization rule written on top of them could be defeated by
# the same request the rule was meant to constrain. A caller could reassign a
# worker profile to somebody else, or write an audit-log entry attributed to
# anyone in the organization.
#
# They are read-only here and filled in from the authenticated session instead;
# see the Derived rules in internal/domain/policy.go for which value each one
# receives and when.
SERVER_OWNED = {
    'worker_profiles': {'user_id'},
    'user_activity':   {'user_id', 'user_email', 'user_name', 'account_type'},
    'job_postings':    {'created_by'},
}


def kind(dt, udt, enums):
    """Classify a column.

    USER-DEFINED covers both enums and extension types: citext reports as
    USER-DEFINED too. Enum-ness is decided by whether pg_enum actually has
    labels for the type, not by data_type alone — classifying citext as an
    enum with no permitted values rejects every email the API is sent.
    """
    if udt == 'uuid':                       return 'KindUUID', 'uuid'
    if dt == 'ARRAY':                       return 'KindTextArray', 'text[]'
    if dt == 'jsonb':                       return 'KindJSON', 'jsonb'
    if dt in ('integer', 'smallint'):       return 'KindInt', 'int'
    if dt == 'bigint':                      return 'KindInt', 'bigint'
    if dt == 'numeric':                     return 'KindFloat', 'numeric'
    if dt == 'boolean':                     return 'KindBool', 'boolean'
    if dt == 'timestamp with time zone':    return 'KindTimestamp', 'timestamptz'
    if dt == 'date':                        return 'KindDate', 'date'
    if dt == 'USER-DEFINED' and enums.get(udt):
        return 'KindEnum', udt
    if udt == 'citext':                     return 'KindString', 'citext'
    return 'KindString', 'text'


def main():
    cols = q("""SELECT table_name, column_name, data_type, udt_name, is_nullable
                FROM information_schema.columns
                WHERE table_schema='public' AND table_name<>'schema_migrations'
                ORDER BY table_name, ordinal_position""")
    enums = collections.defaultdict(list)
    for t, v in q("""SELECT t.typname, e.enumlabel FROM pg_type t
                     JOIN pg_enum e ON e.enumtypid=t.oid
                     JOIN pg_namespace n ON n.oid=t.typnamespace
                     WHERE n.nspname='public' ORDER BY t.typname, e.enumsortorder"""):
        enums[t].append(v)

    by_table = collections.defaultdict(list)
    for t, c, dt, udt, nul in cols:
        by_table[t].append((c, dt, udt, nul == 'YES'))

    o = []
    o.append('// Code generated by scripts/gen_resources.py. DO NOT EDIT BY HAND.')
    o.append('// Regenerate with: make gen-resources')
    o.append('//')
    o.append('// Column names, types, enum values and nullability are read out of')
    o.append('// information_schema so they cannot drift from the migrations. The')
    o.append('// per-resource metadata (path, default sort, default limit, supported')
    o.append('// operations, required fields) comes from docs/api-contract.md.')
    o.append('')
    o.append('package domain')
    o.append('')
    o.append('// AllResources is every resource the API serves.')
    o.append('var AllResources = []*Resource{')
    for tbl in ORDER:
        m = META[tbl]
        if m['ops']:
            ops = ' | '.join('Op' + x for x in m['ops'].split('|'))
        else:
            # No operations means no routes are registered for this resource.
            o.append(f'\t// {m["name"]} serves NO endpoint: useBadges has zero consumers and every')
            o.append('\t// badge the UI renders comes from worker_profiles.earned_badges. The')
            o.append('\t// descriptor exists so the seeder can write the table. api-contract.md §2.')
            ops = '0'
        o.append('\t{')
        o.append(f'\t\tName: {json.dumps(m["name"])}, Path: {json.dumps(m["path"])}, Table: {json.dumps(tbl)},')
        o.append(f'\t\tDefaultSort: {json.dumps(m["sort"])}, DefaultLimit: {m["limit"]},')
        o.append(f'\t\tOps: {ops},')
        if m.get('orgnull'):
            o.append('\t\tOrgNullable: true,')
        o.append('\t\tColumns: []Column{')
        for c, dt, udt, nullable in by_table[tbl]:
            k, cast = kind(dt, udt, enums)
            p = [f'Name: {json.dumps(c)}', f'Kind: {k}', f'PGType: {json.dumps(cast)}']
            if not nullable:      p.append('NotNull: true')
            if c in READONLY or c in SERVER_OWNED.get(tbl, ()):
                                  p.append('ReadOnly: true')
            if c in m['req']:     p.append('Required: true')
            if k == 'KindEnum':
                p.append('Enum: []string{' + ', '.join(json.dumps(v) for v in enums[udt]) + '}')
            o.append('\t\t\t{' + ', '.join(p) + '},')
        o.append('\t\t},')
        o.append('\t},')
    o.append('}')
    sys.stdout.write('\n'.join(o) + '\n')


if __name__ == '__main__':
    main()