// Copyright 2015 Ted Mielczarek. See the COPYRIGHT
// file at the top-level directory of this distribution.

use chrono::{TimeZone, Utc};
use failure::Fail;

use std::ops::Deref;
use std::path::Path;

use minidump::{self, *};

use crate::evil;
use crate::process_state::{CallStack, CallStackInfo, LinuxStandardBase, ProcessState};
use crate::stackwalker;
use crate::symbols::*;
use crate::system_info::SystemInfo;

/// Various advanced options for the processor.
#[derive(Default, Debug, Clone)]
#[non_exhaustive]
pub struct ProcessorOptions<'a> {
    /// The evil "raw json" mozilla's legacy infrastructure relies on (to be phased out).
    pub evil_json: Option<&'a Path>,
}

/// An error encountered during minidump processing.
#[derive(Debug, Fail)]
pub enum ProcessError {
    #[fail(display = "Failed to read minidump")]
    MinidumpReadError(minidump::Error),
    #[fail(display = "An unknown error occurred")]
    UnknownError,
    #[fail(display = "The system information stream was not found")]
    MissingSystemInfo,
    #[fail(display = "The thread list stream was not found")]
    MissingThreadList,
}

impl From<minidump::Error> for ProcessError {
    fn from(err: minidump::Error) -> ProcessError {
        ProcessError::MinidumpReadError(err)
    }
}

/// Unwind all threads in `dump` and return a `ProcessState`.
///
/// # Examples
///
/// ```
/// use minidump::Minidump;
/// use std::path::PathBuf;
/// use breakpad_symbols::{Symbolizer, SimpleSymbolSupplier};
///
/// # std::env::set_current_dir(env!("CARGO_MANIFEST_DIR"));
/// # fn foo() -> Result<(), minidump_processor::ProcessError> {
/// let mut dump = Minidump::read_path("../testdata/test.dmp")?;
/// let supplier = SimpleSymbolSupplier::new(vec!(PathBuf::from("../testdata/symbols")));
/// let symbolizer = Symbolizer::new(supplier);
/// let state = minidump_processor::process_minidump(&mut dump, &symbolizer)?;
/// assert_eq!(state.threads.len(), 2);
/// println!("Processed {} threads", state.threads.len());
/// # Ok(())
/// # }
/// # fn main() { foo().unwrap() }
/// ```
pub fn process_minidump<'a, T, P>(
    dump: &Minidump<'a, T>,
    symbol_provider: &P,
) -> Result<ProcessState, ProcessError>
where
    T: Deref<Target = [u8]> + 'a,
    P: SymbolProvider,
{
    // No Evil JSON Here!
    process_minidump_with_options(dump, symbol_provider, ProcessorOptions::default())
}

/// The same as [`process_minidump`] but with extra options.
pub fn process_minidump_with_options<'a, T, P>(
    dump: &Minidump<'a, T>,
    symbol_provider: &P,
    options: ProcessorOptions,
) -> Result<ProcessState, ProcessError>
where
    T: Deref<Target = [u8]> + 'a,
    P: SymbolProvider,
{
    // Thread list is required for processing.
    let thread_list = dump
        .get_stream::<MinidumpThreadList>()
        .or(Err(ProcessError::MissingThreadList))?;
    // Try to get thread names, but it's only a nice-to-have.
    let thread_names = dump
        .get_stream::<MinidumpThreadNames>()
        .unwrap_or_else(|_| MinidumpThreadNames::default());

    // System info is required for processing.
    let dump_system_info = dump
        .get_stream::<MinidumpSystemInfo>()
        .or(Err(ProcessError::MissingSystemInfo))?;

    let mut os_version = format!(
        "{}.{}.{}",
        dump_system_info.raw.major_version,
        dump_system_info.raw.minor_version,
        dump_system_info.raw.build_number
    );
    if let Some(csd_version) = dump_system_info.csd_version() {
        os_version.push(' ');
        os_version.push_str(&csd_version);
    }

    let linux_standard_base = dump.get_stream::<MinidumpLinuxLsbRelease>().ok();
    let linux_cpu_info = dump
        .get_stream::<MinidumpLinuxCpuInfo>()
        .unwrap_or_default();
    let _linux_environ = dump.get_stream::<MinidumpLinuxEnviron>().ok();
    let _linux_proc_status = dump.get_stream::<MinidumpLinuxProcStatus>().ok();

    // Extract everything we care about from linux streams here.
    // We don't eagerly process them in the minidump crate because there's just
    // tons of random information in there and it's not obvious what anyone
    // would care about. So just providing an iterator and letting minidump-processor
    // pull out the things it cares about is simple and effective.

    let mut cpu_microcode_version = None;
    for (key, val) in linux_cpu_info.iter() {
        if key.as_bytes() == b"microcode" {
            cpu_microcode_version = val
                .to_str()
                .ok()
                .and_then(|val| val.strip_prefix("0x"))
                .and_then(|val| u64::from_str_radix(val, 16).ok());
            break;
        }
    }

    let linux_standard_base = linux_standard_base.map(|linux_standard_base| {
        let mut lsb = LinuxStandardBase::default();
        for (key, val) in linux_standard_base.iter() {
            match key.as_bytes() {
                b"DISTRIB_ID" | b"ID" => lsb.id = val.to_string_lossy().into_owned(),
                b"DISTRIB_RELEASE" | b"VERSION_ID" => {
                    lsb.release = val.to_string_lossy().into_owned()
                }
                b"DISTRIB_CODENAME" | b"VERSION_CODENAME" => {
                    lsb.codename = val.to_string_lossy().into_owned()
                }
                b"DISTRIB_DESCRIPTION" | b"PRETTY_NAME" => {
                    lsb.description = val.to_string_lossy().into_owned()
                }
                _ => {}
            }
        }
        lsb
    });

    let cpu_info = dump_system_info
        .cpu_info()
        .map(|string| string.into_owned());

    let system_info = SystemInfo {
        os: dump_system_info.os,
        os_version: Some(os_version),
        cpu: dump_system_info.cpu,
        cpu_info,
        cpu_microcode_version,
        cpu_count: dump_system_info.raw.number_of_processors as usize,
    };

    let mac_crash_info = dump
        .get_stream::<MinidumpMacCrashInfo>()
        .ok()
        .map(|info| info.raw);

    let misc_info = dump.get_stream::<MinidumpMiscInfo>().ok();
    // Process create time is optional.
    let (process_id, process_create_time) = if let Some(misc_info) = misc_info.as_ref() {
        (
            misc_info.raw.process_id().cloned(),
            misc_info.process_create_time(),
        )
    } else {
        (None, None)
    };
    // If Breakpad info exists in dump, get dump and requesting thread ids.
    let breakpad_info = dump.get_stream::<MinidumpBreakpadInfo>();
    let (dump_thread_id, requesting_thread_id) = if let Ok(info) = breakpad_info {
        (info.dump_thread_id, info.requesting_thread_id)
    } else {
        (None, None)
    };
    // Get exception info if it exists.
    let exception_stream = dump.get_stream::<MinidumpException>().ok();
    let exception_ref = exception_stream.as_ref();
    let (crash_reason, crash_address, crashing_thread_id) = if let Some(exception) = exception_ref {
        (
            Some(exception.get_crash_reason(system_info.os, system_info.cpu)),
            Some(exception.get_crash_address(system_info.os)),
            Some(exception.get_crashing_thread_id()),
        )
    } else {
        (None, None, None)
    };
    let exception_context =
        exception_ref.and_then(|e| e.context(&dump_system_info, misc_info.as_ref()));
    // Get assertion
    let assertion = None;
    let modules = match dump.get_stream::<MinidumpModuleList>() {
        Ok(module_list) => module_list,
        // Just give an empty list, simplifies things.
        Err(_) => MinidumpModuleList::new(),
    };
    let unloaded_modules = match dump.get_stream::<MinidumpUnloadedModuleList>() {
        Ok(module_list) => module_list,
        // Just give an empty list, simplifies things.
        Err(_) => MinidumpUnloadedModuleList::new(),
    };
    let memory_list = dump.get_stream::<MinidumpMemoryList>().unwrap_or_default();
    let memory_info_list = dump.get_stream::<MinidumpMemoryInfoList>().ok();
    let linux_maps = dump.get_stream::<MinidumpLinuxMaps>().ok();
    let _memory_info = UnifiedMemoryInfoList::new(memory_info_list, linux_maps).unwrap_or_default();

    // Get the evil JSON file (thread names and module certificates)
    let evil = options
        .evil_json
        .and_then(evil::handle_evil)
        .unwrap_or_default();

    let mut threads = vec![];
    let mut requesting_thread = None;
    for (i, thread) in thread_list.threads.iter().enumerate() {
        // If this is the thread that wrote the dump, skip processing it.
        if dump_thread_id.is_some() && dump_thread_id.unwrap() == thread.raw.thread_id {
            threads.push(CallStack::with_info(CallStackInfo::DumpThreadSkipped));
            continue;
        }

        let thread_context = thread.context(&dump_system_info, misc_info.as_ref());
        // If this thread requested the dump then try to use the exception
        // context if it exists. (prefer the exception stream's thread id over
        // the breakpad info stream's thread id.)
        let context = if crashing_thread_id
            .or(requesting_thread_id)
            .map(|id| id == thread.raw.thread_id)
            .unwrap_or(false)
        {
            requesting_thread = Some(i);
            exception_context
                .as_deref()
                .or_else(|| thread_context.as_deref())
        } else {
            thread_context.as_deref()
        };

        let stack = thread.stack_memory(&memory_list);

        let mut stack =
            stackwalker::walk_stack(&context, stack.as_deref(), &modules, symbol_provider);

        let name = thread_names
            .get_name(thread.raw.thread_id)
            .map(|cow| cow.into_owned())
            .or_else(|| evil.thread_names.get(&thread.raw.thread_id).cloned());
        stack.thread_name = name;

        stack.last_error_value = thread.last_error(system_info.cpu, &memory_list);

        threads.push(stack);
    }

    // Collect up info on unimplemented/unknown modules
    let unknown_streams = dump.unknown_streams().collect();
    let unimplemented_streams = dump.unimplemented_streams().collect();

    // Get symbol stats from the symbolizer
    let symbol_stats = symbol_provider.stats();

    Ok(ProcessState {
        process_id,
        time: Utc.timestamp(dump.header.time_date_stamp as i64, 0),
        process_create_time,
        cert_info: evil.certs,
        crash_reason,
        crash_address,
        assertion,
        requesting_thread,
        system_info,
        linux_standard_base,
        mac_crash_info,
        threads,
        modules,
        unloaded_modules,
        unknown_streams,
        unimplemented_streams,
        symbol_stats,
    })
}