use super::*;

#[derive(Debug, Clone, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct IntegrationIssue {
    id: String,
    number: u64,
    title: String,
    description: String,
    description_html: bool,
    repository_name: String,
    author: String,
    state: String,
    labels: Vec<String>,
    assignees: Vec<String>,
    web_url: String,
    updated_at: String,
}

#[derive(Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct IssuePage {
    issues: Vec<IntegrationIssue>,
    next_cursor: Option<String>,
}

fn parse_issue(value: &serde_json::Value, provider: &str) -> Option<IntegrationIssue> {
    if value.get("pull_request").is_some_and(|v| !v.is_null()) {
        return None;
    }
    let gitlab = provider.starts_with("gitlab");
    let number = value_u64(value, if gitlab { "iid" } else { "number" });
    if number == 0 {
        return None;
    }
    let reference = value_string(value, &["references", "full"]);
    let repository_name = if gitlab {
        reference
            .rsplit_once('#')
            .map(|(repo, _)| repo.to_string())
            .unwrap_or_else(|| value_u64(value, "project_id").to_string())
    } else {
        let name = value_string(value, &["repository", "full_name"]);
        if name.is_empty() {
            github_repository_name(&value_string(value, &["repository_url"]))
        } else {
            name
        }
    };
    Some(IntegrationIssue {
        id: format!("{provider}:{}", value_u64(value, "id")),
        number,
        title: value_string(value, &["title"]),
        description: value_string(value, &[if gitlab { "description" } else { "body" }]),
        description_html: false,
        repository_name,
        author: value_string(
            value,
            if gitlab {
                &["author", "username"]
            } else {
                &["user", "login"]
            },
        ),
        state: match value_string(value, &["state"]).as_str() {
            "opened" => "open".into(),
            state => state.to_string(),
        },
        labels: value
            .get("labels")
            .and_then(|v| v.as_array())
            .into_iter()
            .flatten()
            .filter_map(|v| {
                v.as_str()
                    .or_else(|| v.get("name").and_then(|n| n.as_str()))
                    .map(str::to_string)
            })
            .collect(),
        assignees: review_names(
            value,
            "assignees",
            if gitlab { "username" } else { "login" },
        ),
        web_url: value_string(value, &[if gitlab { "web_url" } else { "html_url" }]),
        updated_at: value_string(value, &["updated_at"]),
    })
}

fn json_response(
    request: reqwest::blocking::RequestBuilder,
    provider: &str,
) -> Result<serde_json::Value, String> {
    let response = request
        .send()
        .map_err(|err| format!("Could not reach {provider}: {err}"))?;
    if !response.status().is_success() {
        return Err(response_error(response, provider));
    }
    response
        .json()
        .map_err(|err| format!("Invalid {provider} issue response: {err}"))
}

fn azure_issue(value: &serde_json::Value, base: &str) -> IntegrationIssue {
    let field = |name: &str| value_string(value, &["fields", name]);
    let number = value_u64(value, "id");
    let assigned = value_string(value, &["fields", "System.AssignedTo", "displayName"]);
    IntegrationIssue {
        id: format!("azure-devops:{number}"),
        number,
        title: field("System.Title"),
        description: field("System.Description"),
        description_html: true,
        repository_name: field("System.TeamProject"),
        author: value_string(value, &["fields", "System.CreatedBy", "displayName"]),
        state: field("System.State"),
        labels: field("System.Tags")
            .split(';')
            .map(str::trim)
            .filter(|s| !s.is_empty())
            .map(str::to_string)
            .collect(),
        assignees: if assigned.is_empty() {
            vec![]
        } else {
            vec![assigned]
        },
        web_url: format!("{base}/_workitems/edit/{number}"),
        updated_at: field("System.ChangedDate"),
    }
}

fn azure_issues(
    client: &Client,
    base: &str,
    username: &str,
    token: &str,
    cursor: Option<u64>,
) -> Result<IssuePage, String> {
    let condition = cursor
        .map(|id| format!("[System.Id] < {id}"))
        .unwrap_or_else(|| "[System.Id] > 0".into());
    let payload = json_response(client.post(format!("{base}/_apis/wit/wiql"))
        .basic_auth(username, Some(token)).query(&[("api-version", "7.1"), ("$top", "101")])
        .json(&serde_json::json!({"query": format!("SELECT [System.Id] FROM WorkItems WHERE {condition} ORDER BY [System.Id] DESC")})), "Azure DevOps")?;
    let ids: Vec<u64> = payload
        .get("workItems")
        .and_then(|v| v.as_array())
        .ok_or("Azure DevOps returned no work item list.")?
        .iter()
        .filter_map(|v| v.get("id").and_then(|id| id.as_u64()))
        .collect();
    let next_cursor = if ids.len() > 100 {
        Some(ids[99].to_string())
    } else {
        None
    };
    if ids.is_empty() {
        return Ok(IssuePage {
            issues: vec![],
            next_cursor,
        });
    }
    let ids = ids
        .iter()
        .take(100)
        .map(u64::to_string)
        .collect::<Vec<_>>()
        .join(",");
    let payload = json_response(
        client
            .get(format!("{base}/_apis/wit/workitems"))
            .basic_auth(username, Some(token))
            .query(&[("api-version", "7.1"), ("ids", ids.as_str())]),
        "Azure DevOps",
    )?;
    let mut issues: Vec<_> = payload
        .get("value")
        .and_then(|v| v.as_array())
        .ok_or("Azure DevOps returned no work item details.")?
        .iter()
        .map(|v| azure_issue(v, base))
        .collect();
    issues.sort_by_key(|issue| std::cmp::Reverse(issue.number));
    Ok(IssuePage {
        issues,
        next_cursor,
    })
}

#[tauri::command]
pub async fn list_integration_issues(
    provider: String,
    base_url: String,
    username: String,
    token: String,
    cursor: Option<String>,
) -> Result<IssuePage, String> {
    tokio::time::timeout(
        REVIEW_REQUEST_TIMEOUT,
        tauri::async_runtime::spawn_blocking(move || {
            if token.trim().is_empty() {
                return Err("No token is stored for this integration.".into());
            }
            let cursor = cursor
                .map(|c| {
                    c.parse::<u64>()
                        .map_err(|_| "Invalid issue cursor.".to_string())
                })
                .transpose()?;
            let base = normalized_base_url(&base_url)?;
            let client = client()?;
            if provider == "azure-devops" {
                return azure_issues(
                    &client,
                    &base,
                    if username.is_empty() {
                        "gitty"
                    } else {
                        &username
                    },
                    &token,
                    cursor,
                );
            }
            let page = cursor.unwrap_or(1).max(1).to_string();
            let request = match provider.as_str() {
                "github" => client
                    .get(format!("{}/issues", github_api_base_url(&base)?))
                    .bearer_auth(&token)
                    .query(&[
                        ("filter", "all"),
                        ("state", "all"),
                        ("sort", "created"),
                        ("direction", "desc"),
                        ("per_page", "100"),
                        ("page", page.as_str()),
                    ]),
                "gitlab" | "gitlab-self-hosted" => client
                    .get(format!("{base}/api/v4/issues"))
                    .header("PRIVATE-TOKEN", &token)
                    .query(&[
                        ("scope", "all"),
                        ("state", "all"),
                        ("order_by", "created_at"),
                        ("sort", "desc"),
                        ("per_page", "100"),
                        ("page", page.as_str()),
                    ]),
                "gitea" => client
                    .get(format!("{base}/api/v1/repos/issues/search"))
                    .header("Authorization", format!("token {token}"))
                    .query(&[
                        ("type", "issues"),
                        ("state", "all"),
                        ("limit", "100"),
                        ("page", page.as_str()),
                    ]),
                _ => return Err("Unsupported integration provider.".into()),
            }
            .header(USER_AGENT, "Gitty")
            .header(ACCEPT, "application/json");
            let response = request
                .send()
                .map_err(|err| format!("Could not reach {provider}: {err}"))?;
            if !response.status().is_success() {
                return Err(response_error(response, &provider));
            }
            let linked_next = response
                .headers()
                .get("link")
                .and_then(|v| v.to_str().ok())
                .map(|v| v.contains("rel=\"next\""));
            let values: Vec<serde_json::Value> = response
                .json()
                .map_err(|err| format!("Invalid issue list: {err}"))?;
            let next_cursor = if linked_next.unwrap_or(values.len() == 100) {
                Some(cursor.unwrap_or(1).max(1).saturating_add(1).to_string())
            } else {
                None
            };
            Ok(IssuePage {
                issues: values
                    .iter()
                    .filter_map(|v| parse_issue(v, &provider))
                    .collect(),
                next_cursor,
            })
        }),
    )
    .await
    .map_err(|_| "The issue API did not respond within 35 seconds.".to_string())?
    .map_err(|err| format!("Could not load issues: {err}"))?
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;
    #[test]
    fn excludes_pull_requests_and_maps_github_issues() {
        assert!(parse_issue(&json!({"number": 2, "pull_request": {}}), "github").is_none());
        let issue = parse_issue(&json!({"id": 4, "number": 2, "repository_url": "https://api.github.com/repos/team/app", "labels": [{"name":"bug"}], "state":"open"}), "github").unwrap();
        assert_eq!(issue.repository_name, "team/app");
        assert_eq!(issue.labels, ["bug"]);
    }
    #[test]
    fn maps_both_gitlab_variants_and_gitea() {
        for provider in ["gitlab", "gitlab-self-hosted"] {
            let issue = parse_issue(&json!({"id": 8,"iid": 3,"references":{"full":"team/app#3"},"state":"opened","labels":["bug"]}), provider).unwrap();
            assert_eq!(issue.repository_name, "team/app");
            assert_eq!(issue.state, "open");
        }
        let issue = parse_issue(
            &json!({"id":9,"number":4,"repository":{"full_name":"team/app"},"pull_request":null}),
            "gitea",
        )
        .unwrap();
        assert_eq!(issue.repository_name, "team/app");
    }
    #[test]
    fn preserves_custom_azure_states_and_project_identity() {
        let issue = azure_issue(
            &json!({"id":42,"fields":{"System.State":"Ready for QA","System.TeamProject":"Project","System.Tags":"bug; urgent"}}),
            "https://dev.azure.com/org",
        );
        assert_eq!(issue.state, "Ready for QA");
        assert_eq!(issue.repository_name, "Project");
        assert_eq!(issue.labels, ["bug", "urgent"]);
        assert_eq!(
            issue.web_url,
            "https://dev.azure.com/org/_workitems/edit/42"
        );
    }
}