package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"testing"

	"gcy_hpc_server/internal/testutil/testenv"
)

// jobItemData mirrors the JobResponse DTO for a single job.
type jobItemData struct {
	JobID     int32    `json:"job_id"`
	Name      string   `json:"name"`
	State     []string `json:"job_state"`
	Partition string   `json:"partition"`
}

// jobListData mirrors the paginated JobListResponse DTO.
type jobListData struct {
	Jobs     []jobItemData `json:"jobs"`
	Total    int           `json:"total"`
	Page     int           `json:"page"`
	PageSize int           `json:"page_size"`
}

// jobCancelData mirrors the cancel response message.
type jobCancelData struct {
	Message string `json:"message"`
}

// jobDecodeAll decodes the response and returns status, success, and raw data.
func jobDecodeAll(env *testenv.TestEnv, resp *http.Response) (statusCode int, success bool, data json.RawMessage, err error) {
	statusCode = resp.StatusCode
	success, data, err = env.DecodeResponse(resp)
	return
}

// jobSubmitBody builds a JSON body for job submit requests.
func jobSubmitBody(script string) *bytes.Reader {
	body, _ := json.Marshal(map[string]string{"script": script})
	return bytes.NewReader(body)
}

// jobSubmitViaAPI submits a job and returns the job ID. Fatals on failure.
func jobSubmitViaAPI(t *testing.T, env *testenv.TestEnv, script string) int32 {
	t.Helper()
	resp := env.DoRequest(http.MethodPost, "/api/v1/jobs/submit", jobSubmitBody(script))
	status, success, data, err := jobDecodeAll(env, resp)
	if err != nil {
		t.Fatalf("submit job decode: %v", err)
	}
	if status != http.StatusCreated {
		t.Fatalf("expected status 201, got %d", status)
	}
	if !success {
		t.Fatal("expected success=true on submit")
	}

	var job jobItemData
	if err := json.Unmarshal(data, &job); err != nil {
		t.Fatalf("unmarshal submitted job: %v", err)
	}
	return job.JobID
}

// TestIntegration_Jobs_Submit verifies POST /api/v1/jobs/submit creates a new job.
func TestIntegration_Jobs_Submit(t *testing.T) {
	env := testenv.NewTestEnv(t)

	script := "#!/bin/bash\necho hello"
	resp := env.DoRequest(http.MethodPost, "/api/v1/jobs/submit", jobSubmitBody(script))
	status, success, data, err := jobDecodeAll(env, resp)
	if err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if status != http.StatusCreated {
		t.Fatalf("expected status 201, got %d", status)
	}
	if !success {
		t.Fatal("expected success=true")
	}

	var job jobItemData
	if err := json.Unmarshal(data, &job); err != nil {
		t.Fatalf("unmarshal job: %v", err)
	}
	if job.JobID <= 0 {
		t.Fatalf("expected positive job_id, got %d", job.JobID)
	}
}

// TestIntegration_Jobs_List verifies GET /api/v1/jobs returns a paginated job list.
func TestIntegration_Jobs_List(t *testing.T) {
	env := testenv.NewTestEnv(t)

	// Submit a job so the list is not empty.
	jobSubmitViaAPI(t, env, "#!/bin/bash\necho list-test")

	resp := env.DoRequest(http.MethodGet, "/api/v1/jobs", nil)
	status, success, data, err := jobDecodeAll(env, resp)
	if err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if status != http.StatusOK {
		t.Fatalf("expected status 200, got %d", status)
	}
	if !success {
		t.Fatal("expected success=true")
	}

	var list jobListData
	if err := json.Unmarshal(data, &list); err != nil {
		t.Fatalf("unmarshal job list: %v", err)
	}
	if list.Total < 1 {
		t.Fatalf("expected at least 1 job, got total=%d", list.Total)
	}
	if list.Page != 1 {
		t.Fatalf("expected page=1, got %d", list.Page)
	}
}

// TestIntegration_Jobs_Get verifies GET /api/v1/jobs/:id returns a single job.
func TestIntegration_Jobs_Get(t *testing.T) {
	env := testenv.NewTestEnv(t)

	jobID := jobSubmitViaAPI(t, env, "#!/bin/bash\necho get-test")

	path := fmt.Sprintf("/api/v1/jobs/%d", jobID)
	resp := env.DoRequest(http.MethodGet, path, nil)
	status, success, data, err := jobDecodeAll(env, resp)
	if err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if status != http.StatusOK {
		t.Fatalf("expected status 200, got %d", status)
	}
	if !success {
		t.Fatal("expected success=true")
	}

	var job jobItemData
	if err := json.Unmarshal(data, &job); err != nil {
		t.Fatalf("unmarshal job: %v", err)
	}
	if job.JobID != jobID {
		t.Fatalf("expected job_id=%d, got %d", jobID, job.JobID)
	}
}

// TestIntegration_Jobs_Cancel verifies DELETE /api/v1/jobs/:id cancels a job.
func TestIntegration_Jobs_Cancel(t *testing.T) {
	env := testenv.NewTestEnv(t)

	jobID := jobSubmitViaAPI(t, env, "#!/bin/bash\necho cancel-test")

	path := fmt.Sprintf("/api/v1/jobs/%d", jobID)
	resp := env.DoRequest(http.MethodDelete, path, nil)
	status, success, data, err := jobDecodeAll(env, resp)
	if err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if status != http.StatusOK {
		t.Fatalf("expected status 200, got %d", status)
	}
	if !success {
		t.Fatal("expected success=true")
	}

	var msg jobCancelData
	if err := json.Unmarshal(data, &msg); err != nil {
		t.Fatalf("unmarshal cancel response: %v", err)
	}
	if msg.Message == "" {
		t.Fatal("expected non-empty cancel message")
	}
}

// TestIntegration_Jobs_History verifies GET /api/v1/jobs/history returns historical jobs.
func TestIntegration_Jobs_History(t *testing.T) {
	env := testenv.NewTestEnv(t)

	// Submit and cancel a job so it moves from active to history queue.
	jobID := jobSubmitViaAPI(t, env, "#!/bin/bash\necho history-test")
	path := fmt.Sprintf("/api/v1/jobs/%d", jobID)
	env.DoRequest(http.MethodDelete, path, nil)

	resp := env.DoRequest(http.MethodGet, "/api/v1/jobs/history", nil)
	status, success, data, err := jobDecodeAll(env, resp)
	if err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if status != http.StatusOK {
		t.Fatalf("expected status 200, got %d", status)
	}
	if !success {
		t.Fatal("expected success=true")
	}

	var list jobListData
	if err := json.Unmarshal(data, &list); err != nil {
		t.Fatalf("unmarshal history: %v", err)
	}
	if list.Total < 1 {
		t.Fatalf("expected at least 1 history job, got total=%d", list.Total)
	}

	// Verify the cancelled job appears in history.
	found := false
	for _, j := range list.Jobs {
		if j.JobID == jobID {
			found = true
			break
		}
	}
	if !found {
		t.Fatalf("cancelled job %d not found in history", jobID)
	}
}