"""
Tests for Agent Instance mechanism.

Tests cover:
  1. _deep_merge() — dict merging semantics
  2. create_instance() — directory and file creation
  3. load_instance() — merge agent template + instance overrides
  4. load_instance_from_dirs() — two-dir loading
  5. Multiple instances from same template
"""

import json
import os
import shutil
import tempfile

import pytest
import yaml

from agentpaas.engine.instance import (
    _deep_merge,
    create_instance,
    load_instance,
    load_instance_from_dirs,
)


@pytest.fixture
def tmpdir():
    d = tempfile.mkdtemp(prefix="test_instance_")
    yield d
    shutil.rmtree(d, ignore_errors=True)


def _write_yaml(path, data):
    os.makedirs(os.path.dirname(path), exist_ok=True)
    with open(path, "w") as f:
        yaml.dump(data, f, allow_unicode=True)


# ============================================================
# 1. _deep_merge
# ============================================================

class TestDeepMerge:

    def test_simple_override(self):
        base = {"a": 1, "b": 2}
        over = {"b": 3, "c": 4}
        assert _deep_merge(base, over) == {"a": 1, "b": 3, "c": 4}

    def test_nested_merge(self):
        base = {"model": {"name": "qwen", "temperature": 0.3}}
        over = {"model": {"name": "gpt-4"}}
        result = _deep_merge(base, over)
        assert result["model"]["name"] == "gpt-4"
        assert result["model"]["temperature"] == 0.3  # preserved

    def test_deep_nested(self):
        base = {"a": {"b": {"c": 1, "d": 2}}}
        over = {"a": {"b": {"c": 99}}}
        result = _deep_merge(base, over)
        assert result["a"]["b"]["c"] == 99
        assert result["a"]["b"]["d"] == 2

    def test_no_mutation(self):
        base = {"x": {"y": 1}}
        over = {"x": {"y": 2}}
        result = _deep_merge(base, over)
        assert base["x"]["y"] == 1  # base unchanged


# ============================================================
# 2. create_instance
# ============================================================

class TestCreateInstance:

    def test_creates_directories(self, tmpdir):
        inst_dir = os.path.join(tmpdir, "maritime")
        create_instance(inst_dir, "qaagent67wiki", name="Maritime Wiki")

        assert os.path.isdir(os.path.join(inst_dir, "wiki"))
        assert os.path.isdir(os.path.join(inst_dir, "knowledge", "raw"))
        assert os.path.isdir(os.path.join(inst_dir, "knowledge", "processed"))
        assert os.path.isdir(os.path.join(inst_dir, "workspace"))

    def test_creates_instance_yml(self, tmpdir):
        inst_dir = os.path.join(tmpdir, "maritime")
        path = create_instance(inst_dir, "qaagent67wiki", name="Maritime Wiki")

        assert os.path.isfile(path)
        with open(path) as f:
            cfg = yaml.safe_load(f)
        assert cfg["agent"] == "qaagent67wiki"
        assert cfg["name"] == "Maritime Wiki"
        assert "knowledge" in cfg
        assert "wiki" in cfg

    def test_auto_paths(self, tmpdir):
        inst_dir = os.path.join(tmpdir, "finance")
        create_instance(inst_dir, "qaagent67wiki")

        with open(os.path.join(inst_dir, "instance.yml")) as f:
            cfg = yaml.safe_load(f)
        # Paths should point to instance_dir
        assert inst_dir in cfg["knowledge"]["baseDir"]
        assert inst_dir in cfg["wiki"]["dir"]


# ============================================================
# 3. load_instance
# ============================================================

class TestLoadInstance:

    def test_merge_template_and_instance(self, tmpdir):
        # Create agent template
        agent_dir = os.path.join(tmpdir, "agentexample", "myagent")
        _write_yaml(os.path.join(agent_dir, "agent-config.yml"), {
            "type": "react",
            "systemPrompt": "You are helpful",
            "model": {"name": "qwen", "temperature": 0.3},
            "knowledge": {"baseDir": "./knowledge"},
        })

        # Create instance
        inst_dir = os.path.join(tmpdir, "instances", "domain1")
        os.makedirs(inst_dir, exist_ok=True)
        _write_yaml(os.path.join(inst_dir, "instance.yml"), {
            "agent": agent_dir,
            "name": "Domain 1",
            "knowledge": {"baseDir": "/data/domain1/knowledge"},
            "model": {"name": "gpt-4"},
        })

        config = load_instance(os.path.join(inst_dir, "instance.yml"))

        # Template fields preserved
        assert config["type"] == "react"
        assert config["systemPrompt"] == "You are helpful"
        # Instance overrides applied
        assert config["knowledge"]["baseDir"] == "/data/domain1/knowledge"
        assert config["model"]["name"] == "gpt-4"
        # Nested merge: temperature preserved from template
        assert config["model"]["temperature"] == 0.3
        # Metadata injected
        assert config["_agent_dir"] == agent_dir
        assert config["_instance_dir"] == inst_dir
        assert config["_instance_name"] == "Domain 1"


# ============================================================
# 4. load_instance_from_dirs
# ============================================================

class TestLoadInstanceFromDirs:

    def test_with_instance_yml(self, tmpdir):
        agent_dir = os.path.join(tmpdir, "agent")
        inst_dir = os.path.join(tmpdir, "instance")
        _write_yaml(os.path.join(agent_dir, "agent-config.yml"), {
            "type": "simple",
            "systemPrompt": "base",
            "knowledge": {"baseDir": "./kb"},
        })
        os.makedirs(inst_dir, exist_ok=True)
        _write_yaml(os.path.join(inst_dir, "instance.yml"), {
            "agent": agent_dir,
            "knowledge": {"baseDir": "/data/prod/kb"},
        })

        config = load_instance_from_dirs(agent_dir, inst_dir)
        assert config["knowledge"]["baseDir"] == "/data/prod/kb"
        assert config["systemPrompt"] == "base"

    def test_without_instance_yml(self, tmpdir):
        agent_dir = os.path.join(tmpdir, "agent")
        inst_dir = os.path.join(tmpdir, "instance")
        _write_yaml(os.path.join(agent_dir, "agent-config.yml"), {
            "type": "simple",
            "knowledge": {"baseDir": "./default"},
        })
        os.makedirs(inst_dir, exist_ok=True)

        config = load_instance_from_dirs(agent_dir, inst_dir)
        assert config["knowledge"]["baseDir"] == "./default"
        assert config["_instance_dir"] == os.path.abspath(inst_dir)


# ============================================================
# 5. Multiple Instances from Same Template
# ============================================================

class TestMultipleInstances:

    def test_two_instances_share_template(self, tmpdir):
        agent_dir = os.path.join(tmpdir, "template")
        _write_yaml(os.path.join(agent_dir, "agent-config.yml"), {
            "type": "react",
            "systemPrompt": "Wiki agent",
            "knowledge": {"baseDir": "./default"},
        })

        # Instance A: maritime
        inst_a = os.path.join(tmpdir, "maritime")
        os.makedirs(inst_a, exist_ok=True)
        _write_yaml(os.path.join(inst_a, "instance.yml"), {
            "agent": agent_dir,
            "name": "Maritime",
            "knowledge": {"baseDir": "/data/maritime"},
        })

        # Instance B: medical
        inst_b = os.path.join(tmpdir, "medical")
        os.makedirs(inst_b, exist_ok=True)
        _write_yaml(os.path.join(inst_b, "instance.yml"), {
            "agent": agent_dir,
            "name": "Medical",
            "knowledge": {"baseDir": "/data/medical"},
        })

        cfg_a = load_instance(os.path.join(inst_a, "instance.yml"))
        cfg_b = load_instance(os.path.join(inst_b, "instance.yml"))

        # Same template
        assert cfg_a["type"] == cfg_b["type"] == "react"
        assert cfg_a["systemPrompt"] == cfg_b["systemPrompt"]
        # Different data dirs
        assert cfg_a["knowledge"]["baseDir"] == "/data/maritime"
        assert cfg_b["knowledge"]["baseDir"] == "/data/medical"
        assert cfg_a["_instance_name"] == "Maritime"
        assert cfg_b["_instance_name"] == "Medical"